Hi Jon, You can indeed get data with 1 micron(ish) beam. See for example http://journals.iucr.org/d/issues/2008/02/00/wd5082/index.html Different question is whether there is any benefit in using micron size beam. It is subject of much work and discussion (e.g. http://www.nsls.bnl.gov/newsroom/events/workshops/2009/mx/)
Regards, Nukri Ruslan Sanishvili (Nukri), Ph.D. GM/CA-CAT Biosciences Division, ANL 9700 S. Cass Ave. Argonne, IL 60439 Tel: (630)252-0665 Fax: (630)252-0667 rsanishv...@anl.gov -----Original Message----- From: Jon Wright [mailto:wri...@esrf.fr] Sent: Tuesday, April 21, 2009 3:36 PM To: Sanishvili, Ruslan Cc: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] How small is a microbeam? Sanishvili, Ruslan wrote: > .......... Reasons for discriminating > 5-10 micron beams (minibeam) from ca 1 micron (microbeam) might have > been not so much their size but what it involved to achieve these sizes. Might I ask - do you really get data from 1 micron protein crystals? The reduction in scattering power (==crystal volume) from 5x5x5 microns to 1x1x1 is 125 and so it seems to present a grand challenge. I had understood there to be a more fundamental size limit, coming from radiation damage, which is still several microns for typical proteins. Do you suggest that ~1 micron sized crystals are no longer exclusively in the domain of powder diffraction? Millions of crystals working together to increase the signal does help a lot for such tiny ones :-) Going back to the original question, with 'nano' instead of 'micro', the FDA has defined [1] a "100 nm size-range limit of nanotechnology". Name suggetions for 100nm - 999 nm are most welcome. Are they "submicron"? Cheers, Jon [1] http://www.fda.gov/nanotechnology/regulation.html
